People should aim get more protein from vegetable sources rather than meat, to boost life expectancy, a study has suggested.
US researchers writing in JAMA Internal Medicine looked at 30 years’ of diet data for 130,000 people.
They found a reduced risk of early death in people who ate more plant-based protein, and a higher risk in those who ate more animal proteins.
UK experts said more work was needed to find out what was behind the links.
Animal proteins include:
- dairy products
Plant sources include:
- cereals beans
The analysis suggested that for every 3% increase in calories from plant protein, the risk of death from any cause during the period studied was reduced by 10%. It was also associated with a 12% lower risk of death from heart disease.
But increasing the animal protein share of calories by 10% led to a 2% higher risk of all-cause death and an 8% greater chance of dying from a heart problem.
The associations were stronger in people with another risk factor, such as obesity, smoking, drinking heavily or not exercising a lot.
In the study, lifestyle and medical information was collected every two years, and people filled in a questionnaire – about exactly what they had eaten over the previous year – every four years.
Altogether, there were more than 36,000 deaths – almost 9,000 from cardiovascular disease, about 13,000 from cancer and about 14,000 from other causes.
Mingyang Song, from Massachusetts General Hospital, who worked on the study, said: “Our findings suggest that people should consider eating more plant proteins than animal proteins, and when they do choose among sources of animal protein, fish and chicken are probably better choices.
“Future studies should examine the mechanisms underlying the different effects of plant and animal proteins – along with different sources of animal proteins – on overall health.”
Dr Ian Johnson, a nutrition researcher and emeritus fellow at the Institute of Food Research (IFR), said: “This interesting and robust work seems to support the growing consensus that diets based largely on plant foods are better for long-term health than diets containing large quantities of meat and dairy products, but it tells us little about mechanism.
“It is far from clear whether plant proteins are protective or animal proteins are detrimental to health, or whether these protein levels are simply markers for something else.”